JP3967669B2 - High strength aluminum alloy fin material for automobile heat exchanger excellent in rolling property and method for producing the same - Google Patents

Description

【００２８】
【発明の効果】
以上説明したように、本発明の圧延性に優れた自動車熱交換器用高強度アルミニウム合金フィン材及びその製造方法によれば、優れた強度、圧延性を有するフィン材が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum alloy fin material used for a heat exchanger for automobiles manufactured by a brazing method, such as a radiator, and a method for manufacturing the same.
[0002]
[Prior art]
Generally, the fin material, which is a structural member of a heat exchanger used as a radiator of an automobile, is brazed to a refrigerant passage forming body (for example, a pipe material) with an Al-Si brazing material and is metallically bonded to reduce the heat transfer area. By increasing the width, heat exchange efficiency is improved. As the fin material, a pure Al alloy such as AA1050 alloy, an Al-Mn alloy such as AA3003 alloy, an Al-Fe alloy, or the like is used.
With the recent reduction in weight of automobiles, heat exchangers for automobiles are also required to be reduced in weight, and fin materials are also required to be thin and high in strength.
Conventionally, AA1050 alloy, AA3003 alloy and the like are used as fin materials, but Mn: 0.6 to 2.0%, Si: 1.2 to 2.5%, Fe: 0 for the purpose of increasing the strength. 0.05% to 2.0% high strength Al alloy fin material (see Patent Document 1), Mn: 0.5 to 2.0%, Si: more than 0.4 to 2%, Ni: An Al alloy fin material (see Patent Document 2) defined with a composition of 0.1 to 1.0% has been developed.
[0003]
[Patent Document 1]
JP-A-7-90446 (2nd page)
[Patent Document 2]
JP 2000-273565 A (second page)
[0004]
[Problems to be solved by the invention]
However, even such a conventional fin material has a limit in achieving high strength. Moreover, when trying to achieve high strength, the rollability is remarkably inferior, the side cracks during rolling are remarkably large, the yield decreases, and breakage is likely to occur during rolling. Those that are insufficient in strength and self-corrosion resistance or high in strength but lack erosion resistance and thermal conductivity, and those that satisfy all of the thermal conductivity, self-corrosion resistance, erosion resistance and strength There wasn't. The lack of any of the characteristics has caused problems that not only the characteristics required as the fin material of the heat exchanger cannot be satisfied, but also that the performance of the heat exchanger is inevitably deteriorated.
[0005]
In view of the above, the present inventors have studied to obtain a fin material having high strength and excellent rollability. It has been found that this problem occurs particularly when the crystallized product becomes coarse.
Based on the above findings, the present invention provides a high-strength aluminum alloy fin material for automobile heat exchangers excellent in rollability and a method for producing the same.
[0006]
[Means for Solving the Problems]
Among the high-strength aluminum alloy fin materials for automobile heat exchangers excellent in rollability of the present invention for solving the above-mentioned problems, the invention according to claim 1 is by weight%, Mn: more than 2.0 to 3.0% , Si: 0.8 to 1.5%, Fe: 0.05 to less than 0.4%, Zn: 0.1 to 3.0%, the balance is composed of Al and inevitable impurities, and Mn The contents of Si and Fe satisfy the relational expression of Mn / (Si + Fe) ≧ 1.6.
[0007]
The high-strength aluminum alloy fin material for automobile heat exchanger excellent in rollability according to claim 2 further comprises Ni: 0.01 to 1.0% by weight in the invention according to claim 1, The remainder has a composition composed of Al and inevitable impurities, and the contents of Mn, Si, and Ni satisfy the relational expression of Mn− (Si + Ni) ≧ 0.
[0008]
The high-strength aluminum alloy fin material for automobile heat exchanger excellent in rollability according to claim 3 is the invention according to claim 1 or 2, further comprising, in wt%, Zr: 0.05 to 0.20%, Ti : One or two of 0.01 to 0.30% are contained, and the balance has a composition composed of Al and inevitable impurities.
[0009]
The high-strength aluminum alloy fin material for an automotive heat exchanger excellent in rollability according to claim 4 is the invention according to any one of claims 1 to 3, and further, in wt%, In: 0.001 to 0.00. 20%, Sn: One or two of 0.01 to 0.50% are contained, and the balance is composed of Al and inevitable impurities.
[0010]
The method for producing a high-strength aluminum alloy fin material for automobile heat exchanger excellent in rollability according to claim 5 is a high-strength for automobile heat exchanger excellent in rollability having the composition according to any one of claims 1 to 4. In the manufacturing method of an aluminum alloy fin material, the cooling rate at the time of casting shall be 15-1000 degrees C / s.
[0011]
Below, the matter limited by this invention is demonstrated.
Mn: more than 2.0 to 3.0%
Mn crystallizes or precipitates as an intermetallic compound, and improves the strength after brazing. Moreover, an Al—Mn—Si based compound can be formed to lower the Si solid solubility of the matrix and improve the melting point of the matrix. If it is 2.0% or less, the above effect is small, and if it exceeds 3.0%, a coarse crystallized product is formed and castability and rollability are remarkably lowered.
[0012]
Si: 0.8 to 1.5%
Si is dispersed as Al—Mn—Si, Al—Fe—Si, Al—Mn—Si—Fe, and Zr—Si compounds or is dissolved in a matrix to improve the strength. In addition, the formation of such a compound reduces the solid solubility of Mn and Zr after brazing and improves thermal conductivity. If the content is less than 0.8%, the above effect is small. If the content exceeds 1.5%, coarse crystals are formed, and the castability and rollability are remarkably lowered. Moreover, melting | fusing point falls and it fuse | melts at the time of brazing. Furthermore, Si solid solubility increases and thermal conductivity falls.
[0013]
Fe: 0.05 to less than 0.4% Fe crystallizes or precipitates as an intermetallic compound, and improves the strength after brazing. In addition, Al—Mn—Fe, Al—Fe—Si, and Al—Mn—Fe—Si based compounds are formed to reduce Mn and Si solid solubility in the matrix and improve thermal conductivity. If it is less than 0.05%, the above effect is small, and if it is 0.4% or more, a coarse crystallized product is formed and castability and rollability are remarkably lowered.
[0014]
Zn: 0.1-3.0%
Zn has a lower potential than the non-joining member and acts as a sacrificial anode material. If it is less than 0.1%, the above effect is small, and if it exceeds 3.0%, the self-corrosion rate is remarkably increased.
[0015]
Mn / (Si + Fe) ≧ 1.6
It is preferable to satisfy the above relational expression because the crystallized material is refined so that the strength is improved and the rollability is not lowered. If the relational expression is less than 1.6, the crystallized material is coarsened, and the rollability is lowered and the strength is lowered.
[0016]
Ni: 0.01 to 1.0%
Ni crystallizes or precipitates as an intermetallic compound, and improves the strength after brazing. If it is less than 0.01%, the above effect is small, and if it exceeds 1.0%, the self-corrosion rate is remarkably increased. In addition, since an Al—Mn—Ni based compound is formed, excessive single Si is formed, resulting in a decrease in the solidus temperature and being easily melted during brazing.
[0017]
Mn- (Si + Ni) ≧ 0
It is preferable to satisfy the above relational formula because simple Si that does not form a compound dissolves in the fin material matrix and lowers the melting point. When the relational expression is not satisfied, problems such as being susceptible to erosion due to melting brazing during the brazing heat treatment and melting of the fin material itself occur.
[0018]
Zr: 0.05 to 0.20%, Ti: 0.01 to 0.30%
Zr and Ti are dispersed as fine intermetallic compounds after brazing to improve the strength. When Zr: less than 0.05% and Ti: less than 0.01%, the above effects are small, and when Zr: more than 0.20% and Ti: more than 0.30%, castability and rollability are remarkably lowered. To do.
[0019]
In: 0.001 to 0.20%, Sn: 0.01 to 0.50%
In and Sn have a lower potential than the non-joining member and act as a sacrificial anode material. When In: less than 0.001% and Sn: less than 0.01%, the above effects are small, and when In: more than 0.20% and Sn: more than 0.50%, the self-corrosion rate is remarkably increased. In addition, the rollability is reduced.
[0020]
Cooling rate during casting: 15 to 1000 ° C./s
When the cooling rate at the time of casting is 15 to 1000 ° C./s, the cooling rate is fast, so that formation of coarse crystals can be suppressed, and further improvement in rolling properties and strength can be achieved. In addition, since a further effect is not acquired even if it makes a cooling rate higher than 1000 degrees C / s, a cooling rate is set to 15-1000 degrees C / s.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
The aluminum alloy used for the fin material of the present invention can be produced by a conventional method according to the above composition. The manufacturing method of the fin material of the present invention is not limited. The fin material obtained as described above is usually subjected to corrugation to obtain fins. The fins are assembled, for example, by being installed between tubes, and a brazing process is performed to obtain a heat exchanger.
[0022]
【Example】
An aluminum alloy having the composition shown in Table 1 was cast at a different cooling rate during casting, and subjected to hot rolling and / or cold rolling, intermediate annealing, and cold rolling to obtain a rolled material having a thickness of 0.06 mm. Produced.
[0023]
Tensile strength after brazing As an evaluation of the strength of the fin material after brazing, the fin material itself was brazed equivalently in a high-purity nitrogen gas atmosphere (600 to 610 ° C. × 5 minutes, cooling rate 100 ° C./minute). A tensile test was performed to measure the tensile strength. Since the tensile strength of the conventional fin material produced using the AA3003 alloy was 110 MPa, it was determined that a material having a tensile strength of 145 MPa or more was sufficiently strong.
[0024]
The rollability of the rollable fin material was evaluated by a value obtained by dividing the total length of side cracks after rolling by the length of the material after rolling. After rolling to a plate thickness of 2 mm, the end face was cut under the same conditions to obtain a sample of 200 mm length × 100 mm width. Thereafter, intermediate annealing was performed at 560 ° C. for 60 s (the conditions were set so that all materials were completely softened). Then, cold rolling was performed to 0.1 mm, and rollability was evaluated. In addition, it was judged that the side crack of less than 0.5 mm does not become a problem substantially, and the side crack of 0.5 mm or more was made into object. If it was 0.15 or less, it was judged that the rollability was sufficient.
[0025]
In order to evaluate the erosion caused by brazing during the brazing heat-resistant brazing heat treatment and the buckling of the fin material due to the melting of the fin material itself, the melting of the fin material starts when the temperature is raised at a rate equivalent to brazing heat treatment at 10 ° C / min. The temperature was investigated. Since the brazing heat treatment temperature is about 600 ° C., it was judged that the fin material melting start temperature is 610 ° C. or more has sufficient brazing erosion resistance.
[0026]
The results of each evaluation are shown in Table 1. All of the materials of the present invention exhibited excellent strength and rollability.
[0027]
[Table 1]

[0028]
【The invention's effect】
As described above, according to the high-strength aluminum alloy fin material for automobile heat exchanger excellent in rollability of the present invention and the manufacturing method thereof, a fin material having excellent strength and rollability can be obtained.

Claims (5)

% By weight, Mn: more than 2.0 to 3.0%, Si: 0.8 to 1.5%, Fe: 0.05 to less than 0.4%, Zn: 0.1 to 3.0%, Automotive heat excellent in rollability, characterized in that the balance is composed of Al and inevitable impurities, and the contents of Mn, Si and Fe satisfy the relational expression of Mn / (Si + Fe) ≧ 1.6 High-strength aluminum alloy fin material for exchangers. Furthermore, Ni: 0.01-1.0% is contained by weight%, Content of Mn, Si, and Ni satisfies the relational expression of Mn- (Si + Ni)> = 0. 1. A high-strength aluminum alloy fin material for automobile heat exchangers having excellent rollability according to 1. Furthermore, 1% or 2 types of Zr: 0.05-0.20% and Ti: 0.01-0.30% are contained by weight%, The 1 or 2 characterized by the above-mentioned. High strength aluminum alloy fin material for automotive heat exchangers with excellent rolling properties. Furthermore, 1% or 2 types in In: 0.001-0.20% and Sn: 0.01-0.50% are contained by weight%, Any of Claims 1-3 characterized by the above-mentioned. A high-strength aluminum alloy fin material for automobile heat exchangers having excellent rolling properties as described in Crab. In the manufacturing method of the high intensity | strength aluminum alloy fin material for motor vehicle heat exchangers which has the rolling property which has the composition in any one of Claims 1-4, the cooling rate at the time of casting shall be 15-1000 degrees C / s. A method for producing a high-strength aluminum alloy fin material for automobile heat exchangers with excellent rolling properties.